title: Synthesis of an orthogonal topological analogue of helicene.
abstract: The synthesis of an orthogonal topological pentamer analogue of helicene is presented. This analogue forms a tubular structure with its aromatic systems directed parallel to the axis of propagation, which creates a cavity with the potential to function as a host molecule. The synthetic strategy reported, based on a series of repeating Friedländer condensations that utilize pyrido[3,2-d]pyrimidine moieties as protected amino aldehydes, allows for the facile access of higher generations of helical, tubular structures. As a result of the synthetic strategy, only a helical isomer of the pentamer is possible. The structure and absolute configuration of the pentamer were elucidated from a combination of NMR spectroscopic data, optical properties, X-ray structures, and by comparison of an experimental electronic circular dichroism spectrum to a calculated spectrum.
authors.affiliation: Centre for Analysis and Synthesis, Lund University, P.O. Box 124, 221 00, Lund (Sweden), Fax: (+46) 46-2228209.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Wixe
authors.forename: Carl-Johan
authors.initials: CJ
authors.lastname: Wallentin
authors.forename: Magnus T
authors.initials: MT
authors.lastname: Johnson
authors.forename: Peter
authors.initials: P
authors.lastname: Fristrup
authors.forename: Sven
authors.initials: S
authors.lastname: Lidin
authors.forename: Kenneth
authors.initials: K
authors.lastname: Wärnmark
keywords: bicyclic compounds; circular dichroism; helical structures; pyridopyridines; quinolines